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Thursday, February 27, 2014

Following failure of the 7.62mm M73 tank machine guns, in
around 1970, US Army decided to try some unorthodox solutions for a compact yet
simple and reliable tank machine gun in the form of an externally powered
weapon.

An additional benefit of an external power solution is that such
weapon, if properly timed, will not leak powder gases back into the tank
interior.

Initial work was commenced by the Hughes Tool Co, under contract to
the US Army Weapons Command. The test weapon, unofficially known as EPAM
(Externally Powered Armor Machine gun) used a 24VAC electric motor, which
operated dual belt feeds and a rotating cylinder with cam slot that operated
the reciprocating bolt.

The test weapon fired at about 550 round per minute,
and had forward ejection through a long tube, so spent cases would fall outside
the tank interior.

For various reasons, however, this system was abandoned in
favor of the so called “Chain Gun” system, developed by the same Hughes Tool Co
in around 1973.

The basic principle involved an externally driven endless chain
that ran around the receiver and operated a more or less traditional rotating
bolt and bolt carrier through a single abutment, fixed to the chain.

This
principle was used to develop a wide array of weapons, including a 30mm
helicopter gun for the AH64 Apache helicopter, several automatic cannon of the
“Bushmaster” family, and one 7.62mm machine gun, the EX34.

Despite the fact
that “Chain Gun” automatic cannon found wide acceptance in US Service and
abroad, the “smaller brother” of the family found no luck in the US Armed
forces; however, it was adopted as a vehicle gun in UK and Canada and is manufactured
under license by Colt Canada (former DIEMACO) in Canada.

Also, in 2011 US-based
ATK Corporation announced its newest addition to the “Bushmaster” family of
externally operated weapons, the “Bushmaster 7,62mm” tank machine gun.

This
weapon appears to be modified and slightly shortened and lightened version of
the old “7,62mm Chain gun”.

This is an image showing the mechanism from an old report dated 1982 for the then called the Hughes Helicopter 7.62mm Chaingun.

Here is an image I've found from arcforums that shows a Hughes 7.62mm Chaingun on a AH-6E helicopter:

The British variant of the 7.62mm chaingun from the Challenger MBT is shown in the image below:

So this 'old' new gun is now offered again from ATK.

So what makes this gun so special:

- It's been designed from the ground for turret applications.

- It is electric powered and does not use propellant gases or recoil to drive the bolt

- This means you do not need fancy and complex electric chargers for your turret application. That eliminates one important problem.

- It has got a belt pull force in excess of the link strength; which means you can put a huge ammo box say 1.000 rounds in your turret and you dont need a powered forwarder to assist the gun. That eliminates another problem.

- The spent cases are ejected automatically to the outside from the frontal eject port. There goes another pain in the a** for the case collector or case eject chute.

- The gun is mounted using an easy to implement bayonet mount and does not need any recoil absorbers or soft mounts. So you dont need a fancy gun mount.

-You can change the barrel from inside the turret which is another nice feature

- There is much less fumes blown inside the turret compared with the gas operated guns.

- And this gun comes in a package that weighs only 15kg's.

It seems these advantages for turret applications was notified by Norwegians and Hagglunds of Sweden 'cause the new CV9030 for Norway comes with the 762mm Chaingun as seen below:

Sunday, February 23, 2014

Alternative for the Venerable M2 .50cal/12.7mm for Remote Weapon Station Integration:

Rheinmetall RMG.50

The venerable 'Ma Deuce' has been the only heavy machine gun that has seen widespread service in western armies.

With the introduction of the remote weapon stations (RWS) and Remote Turrets, M2 immediately has been the weapon of choice for these systems because of its longer reach and high energy.

However, it is not a simple task to integrate M2 in a remote controlled system. The cocking mechanism and the trigger needs to be remotely controlled. This ended up, the M2 guns being equipped with linear actuators or ball screw mechanisms to perform charging and solenoids for remote trigger actuation. Some M2's in RWS systems even have remote safing mechanisms.

This resulted in some electric driven 12.7mm machine guns as an alternative to M2 for RWS installations. One of them is the Rheinmetall's RMG.50.

Rheinmetall RMG.50

Rheinmetall's development is called RMG.50 and the development started for German Army. The version for the German army is called SMG50 (Schwere Machinengewehr) and the export version is called RMG.50.

Main components are shown below:

The gun is electrically driven and it has a stronger muzzle and chamber than M2. This resulted the possibility of using a higher pressure cartridge than the standard 12.7mmx99 cartridge, which will enable 14.5mm cartridge lethality and range in a 12.7mm gun.

Sunday, February 9, 2014

Combat Vehicle 90, CV90 is arguably if not the best, one of the top three IFV types in the world today.

The one shown here is the Dutch variant, CV9035 armed with a Bushmaster III 35mm autocannon that has a lethality one step ahead of the competition.

Spz PUMA

Spz Puma is the German Army, Bundeswehr's new generation IFV that is entering service.

Latest example of fine German engineering, Puma delivers a good combination of protection, firepower and mobility. It is equipped with an unmanned turret armed with Mk30-ABM 30mm autocannon.

M2A3 BRADLEY

Although a product of the 80's, constant upgrades still kept Bradley one of the finest.

With the latest update package, M2A3 BUSK (Bradley Urban Survivability Kit), it is now a keen city fighter as well. Bradley also distinguishes itself with its proven battle record from 1991 Desert Storm to Kosova and Iraq in 21st century.

The only drawback in today's battlefields would be the 25mm Bushmaster, which although is an excellent weapon, might be a little on the lighter side considering the increasing protection levels.

K21

Korean K21 Next Generation IFV is beginning to enter Korean Army service.

It is one of the newest vehicles with the development effort began in 1999. Its 25 tons combat weight is propelled by a 740HP diesel engine.

The turret has a highly effective fire control system that enables the large 40mm autocannon to fire at moving targets from the moving vehicle with a high accuracy.

ZBD-08 ( WZ502G)

China's latest IFV is the ZBD-08 or WZ502G. It is an updates version of the ZBD-04. The vehicle has its origins from the Russian BMP3, however the chassis is widely changed with the powerpack in the front and squad compartment at the back.

The turret is still the BMP3 turret with a 100mm cannon and 30mm autocannon.

BMP-3

Like the Bradley, another vehicle from the Cold War. It's been upgraded from its service entry of 1987.

The vehicle is prominent in terms of its firepower consisting of 100mm 2A70 rifledgun that can fire conventional shells or 9M117 ATGM's; 2A72 30mm dual-feed autocannon and a 7.62mm PKT machinegun in the turret; plus two more 7.62mm PKT's in the bow.

The vehicle serves in 11 countries armed services worldwide making it the most widely used modern IFV.

Tuesday, February 4, 2014

The Soviet-Afghan War and the Chechen Wars emphasized the tactical gap for the Soviets and the Russians. The enemy was not modern, mechanized, nor arrayed in a defense in-depth. Their RPG gunners knew where the soft spots were on the various Soviet/Russian vehicles.

The terrain worsened the problem of the tactical gap and, in the areas where the tanks could go, tanks and BMPs were often separated and unable to support each other. In the mountains of Afghanistan, the tanks were often left behind and the BMPs and BTRs had to accomplish an independent mission they were not designed for. The Russians decided that the tactical gap between tanks and mechanized infantry is almost inevitable.

The battle of Grozny on New Year’s Eve 1994 provided the impetus to develop a heavily armored close combat system. The Russians discovered that the thinly armored ZSU 23-4 self-propelled antiaircraft gun was the optimum system for tank support in city fighting, but its vulnerability offset the efficiency of its four 23mm automatic cannons.

To ensure the survivability of tanks, they needed a new system that was built like a tank, but provided mutual close combat support. The new system should provide protection against enemy antitank weapons, infantry, strong points, helicopters, and fixed wing aviation. The new system needed to be an integral

part of the armored unit.

Ref: Grau, L., W., "Preserving Shock Action", ARMOR, Sept, Oct, 2006.

What they needed was a heavily armored-highly survivable vehicle that has the weapons for defeating the obstacles and unconventional forces encountered in the urban battlefield. These weapons should have high lethality and the means to engage upper floors of the buildings.

The Russian answer was the BMPT tank support vehicle. The BMPT [Beovaya mashina podderzhki tankov] is built on a T-72 tank chassis, so it has the armored protection, maneuverability, and ruggedness to maneuver directly with the tank platoon. It has laminated and reactive armor and weighs 47 tons and carries a five-man crew.

And the Russians somehow created the land equivalent of the Mi-24 Hind helicopter. Just looking at the weapons integrated to BMP-T is enough to drop your jaw.

The rear of the driver's compartment, at the front of the vehicle, has been raised, providing greater internal volume. It has a new turret that is equipped with two 30 mm 2A42 dual-feed cannons with a cyclic rate of fire of up to 600 rds/min. A total of 850 rounds of ready use ammunition can be carried. The cannon can fire a wide range of ammunition types including: High Explosive - Tracer (HE-T), Armour-piercing discarding sabot (APDS), High Explosive Fragmentation (HE-FRAG) and Armor-Piercing - Tracer (AP-T).

A 7.62 mm machine gun is mounted coaxially with the main armament.

Four launchers for the Ataka-T anti-tank guided missile(ATGM), which can fire a variety of different warheads, are mounted on either side of the main armament. These include a tandem HEAT warhead to defeat targets fitted with explosive reactive armour.

To enable the BMPT to engage targets in both day and night conditions and when the BMPT is stationary or moving, a computerized fire-control system is fitted. It uses proven elements from those fitted to theT-90 MBT. The commander is equipped with a panoramic sight B07-K1, the gunner has a B07-K2 sight with optical and thermal channels and a laser rangefinder.

The two operators for the AG-17D 30mm Automatic Grenade Launchers each have an "Agat-MR" day/night sight.

As an option, the BMPT can be fitted with mine-clearing devices such as the KMT-7 or KMT-8 mine sweepers.

Sunday, February 2, 2014

Logistics convoys, especially in today's asymmetrical battlefields, are one of the most risky missions for both manpower and material losses.

US Army TARDEC (Tank Automotive Research Development and Engineering Center) and Lockheed Martin in early January has demonstrated a fully autonomous convoy in Fort Hood, Texas.

This demonstration has proven the feasibility of unmanned convoys. Watch the video, it is impressive!

The convoy consisted of M1915 and Palletized Loading System (PLS) - an Oshkosh HEMTT variant.

The unmanned vehicles were equipped with GPS and LIDAR sensors for autonomous operation. LIDAR sensors use infrared or ultraviolet lasers to illuminate the terrain immediately to the front of the sensor and use the reflected light to create a 3D map of the world in front of the vehicle for navigation and obstacle avoidance.

We might expect the convoys in the near future's battlefields roam the countryside without any humans in control.